def binary_search(mylist,item):
'''
二分查找法
在100中猜中一个数
'''
low = 0
hight = len(mylist)-1
while hight >= low :
mid = (low + hight)//2
guess = mylist[mid]
if guess == item:
return guess
if guess < item:
low = mid + 1
else:
hight = mid -1
return None
mylist = list(range(1,101))
print(binary_search(mylist,45))
print(binary_search(mylist,1523))